et al. - Westland District Council · PDF filetaxonomic resolution that were used for identification, two invertebrate species were ... but is likely to be an error (Palmer 2010)

McKaysCreek/KaniereForksHydroelectricPowerSchemeReconsentingAquaticEcologyAssessmentofEffects 51

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Thebarspacingofthe trashrackin theKanierewaterracerangesfrom60‐70mm

(Figure 4.22). The bars slope downstream away from the base at an angle of

approximately63degreesandareatrightanglestotheflowwithnobypass.Three

measurementsofwatervelocityweremadeapproximately1minfrontofthetrash

rackandthemaximumapproachvelocitywas0.81m/s.Thewaterracewasflowing

nearitsfullcapacityof1cumecatthetimeofmeasurement.

Figure4.22 KaniereWaterRacetrashrack.

(ii) Spawningescapementoffemalelongfineels

In order to estimate the number of adult female longfin eels (length greater than

700mm) that might be expected to emigrate downstream from Lake Kaniere

annually, the information containedwithin Graynothet al. (2008)was used. Lake

Kaniere is classifiedasaClass2eel fishery,whichmeans that it isprotected from

fishing in its upper reaches but migrant eels could be fished further downstream

(Graynoth et al. 2008). For comparison, Class 1 fisheries have not been

commercially fished (e.g. National Parks) and also have safe downstream passage

formigrating female eels (Graynothet al. 2008). Graynothet al. (2008) estimated

thebiomassoflongfineelsinLakeKanieretobe12tonnes.Largefemalelongfineels

areestimatedtocomprise74%ofthetotalweightoflongfineelspresentinClass2


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waters(Graynothetal.2008).ThebiomassoffemalelongfineelsinLakeKaniereis

therefore calculated to be 8.88 tonnes. Graynothet al. (2008) estimated that only

8.3%offemale longfineels inClass2watersmatureandmigratetoseaeachyear,

thisequatesto0.737tonnesor737kginLakeKaniere.Theestimatedmeanweight

of large female eels is 1.5kg (Jellyman et al. 2000 cited in Graynoth et al. 2008).

Therefore 491 large female eels are estimated to migrate downstream from Lake

Kaniereannually.Note thatthisestimateisheavilydependenton themeanweight

andisarelativelyrudimentarydesktopcalculation.

5. SummaryofExistingAquaticEcosystem

There is limited informationonwaterqualitywithin theKaniereRivercatchment;

however,fromtheinformationavailable,andthemoderateamountofdevelopment

inthecatchment,itisexpectedthatwaterqualityisgood.Watertemperaturesinthe

residual river belowMcKaysweir exceeded20°C on several days during February

2010andamaximumtemperatureof23°Cwasrecorded.

PeriphytonwasvisibleatallsitesintheKaniereRiver.Longfilamentousgreenalgae

werepresentatall sitesandcoverslightlyexceededaesthetic/recreationguideline

levelsatonesite.Theflowinthisreachwasapproximately5cumecs,havingbeen

reducedbythe1cumecKaniereintakeupstream.It isunlikelythatthis small flow

reduction would have caused algae cover to exceed guideline levels, and natural

catchment features (including the presence of a lake upstream resulting in a

relatively stable flowregime)andhabitat conditionsat the timewouldhavehad a

greater influence. Thick algae mats were also present at all sites; however,

aesthetic/recreationguidelinecoverlevelsforcyanobacteria/diatommatswerenot

exceeded at any sites. Periphyton biomass (chlorophyll a) did not exceed

aesthetics/recreationguidelinesatanysites.

The benthic macroinvertebrate community of the Kaniere River is comparable to

that of similar habitats in theWest Coast region. A total of 40 macroinvertebrate

taxa were identified in our survey of six sites in the river. Within the limits of

taxonomic resolution that were used for identification, two invertebrate species

were identified as threatened: the freshwater mussel (kākāhi) and freshwater

crayfish(koura),whicharebothrankedtobein‘gradualdecline’(Hitchmoughetal.


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2007). Common macroinvertebrate taxa included, Aoteapsyche net‐spinning

caddisflies, Potamopyrgus snails, Elmidae beetles, Oxyethira albiceps cased

caddisflies and Deleatidium mayflies. The dominant taxa varied somewhat

depending on the distance of a site downstream from the lake.Macroinvertebrate

communityindices(%EPTtaxa,andMCIandQMCIscores)weregenerallyindicative

of‘fair’to‘good’qualityinvertebratehabitat.

Seventeen fish species have been recorded in the Kaniere River catchment, 13 of

these native and four introduced. Brown trout are common in both the lower

Kaniere River and Lake Kaniere; however, angler use of the Kaniere River is low.

TherangeofnativefishspeciespresentintheKaniereRivercatchmentissimilarto

thatofotherWest Coast rivers. Thereare obviousdifferences in fishcommunities

upstream and downstream of McKays weir, and common bully and giant kokopu

populationsinLakeKanierebothappeartobenon‐diadromous.

A threat ranking process has recently (June 2009) been applied to New Zealand

freshwater fish (Allibone et al. 2010). These rankings supersede the rankings

conductedunderthesystemofMolloyetal.(2002),aslistedinHitchmough(2002)

and Hitchmough et al. (2007). The rankings include all described species, and

genetically distinct but undescribed taxa.Under the previous ranking system four

species found in the Kaniere River catchmentwere classified as threatened; giant

kokopu and longfin eel were both ranked as in ‘gradual decline’ and shortjaw

kokopu and lampreywere ranked as ‘sparse’ (Hitchmoughet al. 2007). Under the

new ranking system these four species are all classified as ‘declining’, with the

qualifiers of ‘partial decline’ for giant kokopu, and ‘data poor’ for lamprey and

shortjawkokopu(Alliboneetal.2010).Afurtherfivespeciesarealsonowclassified

as ‘declining’; bluegill bully (‘data poor’), inanga (‘conservation dependent’, ‘data

poor’),koaro,redfinbullyandtorrentfish(Alliboneetal.2010).


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6. AssessmentofEffects

6.1 Background

TPL is considering upgrading and improving the efficiency of the scheme. The

proposedenhancementstoKaniereForksandMcKaysCreekareinbrief(presented

indetailinSection1.1):

• Increase abstraction to Kaniere race to 8 cumecs (requiring

deepening/heightening or widening of race) and construct new Kaniere

PowerStationatWardsRoad(dischargetoKaniereRiveratthispoint).

• Increase abstraction to McKays race to 8 cumecs (requiring

deepening/heightening or widening of race) and increase discharge from

McKayspowerstationto9cumecs.

Under the enhanced scheme flows will vary in different locations in the Kaniere

River.Asanindicationas tohowriverflowswillbealteredrelativeto theexisting

situationTable 6.1shows simulatedminimum,median,meanandmaximumflows

for five locations under the existing and enhanced schemes for the January 2002‐

December2008period.Thepotential effectof these flow changeson fish passage,

water quality, and instream habitat are discussed in the following sections. This

analysis is based on the predicted flows provided to us by TPL and therefore its

accuracyisdependentontheaccuracyoftheflowpredictions.


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Table6.1 Simulated3hourlyminimum,median,meanandmaximum flows (cumecs) forthe period January 2002December 2008 at five locations in theKaniereRiverundertheexistingoperatingregimeandtheenhancedscheme(dataprovidedbyLenniePalmer,TPL).

Operating regime

Flow statistic

1. Downstream of lake outlet

2. At Wards

Road Station

3. Downstream of McKays

weir

4. Downstream of Kaniere

Forks Station


Creek Station

Existing Minimum 0.92 0.95 0.20* 0.26 0.82 Median 5.5 5.8 1.4 2.9 7.5 Mean 6.1 6.4 2.9 5.1 10.8 Maximum 41 42 53 75 144

Enhanced Minimum 0.30 0.40 0.30 0.38** 0.74 Median 0.33 7.9 0.31 0.68 9.0 Mean 0.56 7.4 1.2 2.4 11.4 Maximum 25 34 38 73 160 * A minimum flow value of 0 cumecs has been derived from McKays Weir level record, but is likely to be an error

(Palmer 2010). The consented minimum flow of 0.20 cumecs has therefore been used. ** Note that this minimum flow is calculated on the requirement to achieve a minimum flow of 0.5 cumecs

downstream at McKays Ford.

6.2 Fishpassage

6.2.1Background

AllofthenativefishspeciesfoundintheKaniereRivercatchmentarediadromous

(except brown mudfish), requiring access to and from the sea to complete their

lifecycle. Common bully and giant kokopu populations in Lake Kaniere are land‐

locked,however,juvenilesofthesespeciesmaystillundergodownstreammigration

(Paterson and Boubee 2010). The two intake and control structures within the

Kaniere River mainstem associated with the scheme (i.e., McKays weir and Lake

Kaniere outlet control structure) could therefore limit upstream and downstream

fishpassage.ThereisalsoaweirassociatedwiththeintakestructureinBlueBottle

Creek.

6.2.2 Intakescreening

Therearecurrently twolocationswherewater istakenfromtheKaniereRiverfor

the McKays Creek/Kaniere Forks scheme. Additional water is also taken into the

McKaysschemefromBlueBottleCreek.Attheintakes thereisarisk thatfishmay

becomeentrainedwithintheintakeraces.Whetherornotfishwillbeentrainedinto

theracesdependsonthemeshsizeandapproachvelocitiesoftheintakescreen.

Arecentreviewofscreeningrequirementsforjuvenilenativefishandsalmonidsat


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irrigation water intakes in Canterbury recommends that mesh sizes of

approximately 3mm are necessary to exclude most juvenile fish (Jamieson et al.

2007)(Table6.2).Screenmeshsizesof20mmandapproachvelocitiesof lessthan

or equal to 0.5m/s have been recommended to exclude the majority of female

migranteels(Charteris2006,PatersonandBoubee2010)(Table6.2).

Table6.2 Screenmeshsizesrequiredtoexcludefishfromwaterintakes.InformationfromCharteris(2006)andJamiesonetal.(2007).

Group Mesh size (mm) Juvenile salmonids 3 Native larval fish ≤1 Whitebait (banded kokopu, inanga), common bully 3 Juvenile torrentfish 3 Glass eels and elvers 1.5-3 Adult eels 20-25

The Kaniere Forks water race intake at the lake outlet is currently unscreened;

however, there is a trash rack located approximately 3km further downstream in

the race. The McKays race intake at McKays weir also has a trash rack. The bar

spacingoftheMcKaysandKanieretrashracksrangefrom60‐70mmwithapproach

velocitiesexceeding0.5m/s.ThereisnoscreeningattheBlueBottleCreekintake.

ThebarspacingofthetrashracksintheKanierewaterraceandattheintaketothe

McKays race are therefore not narrow enough to exclude any native fish species.

Most fish would pass through the trash rack to enter the race, but approach

velocities are such that adult eelsmay insteadbecome impinged against the bars.

Migrating adult eels, however, tend tomove downstreamduring freshes or floods

and it is likely that they would travel in the main flow of the river, towards the

middleofthechannel.Theywouldthereforebelesslikelytoencountertheintakes

tothewaterraces,butratherbypassoverMcKaysweirandcontinuedownstream.

ThisissupportedbytheobservationofTPLstaffthattheyhaveneverencountered

dead eels on the trash racks during their regular maintenance (routinely every

seconddayandmoreoftenduringhighriverlevels)(JimMcDermott,pers.comm.).

There is suitable fish habitat within the McKays/Blue Bottle Creek and Kaniere

water races for some distance downstream of each intake and fish have been

observedineachofthesewaterraces (Section4.3).However, furtherdownstream


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thewatereventuallyenterspenstockstobeconveyedtoeachpowerstation.There

is a second trash rack in the Kaniere race immediately upstream of the Kaniere

Forkspenstocks.Ithasabarspacingof45mm,whichisalsonotsufficienttoexclude

native fish. The trash rack at the McKays Creek penstocks has a bar spacing of

25mm,which shouldbe sufficient toexclude largeadulteels,but not smaller fish.

Most diadromous fish that enter the races as part of their active downstream

migrationwillthereforeultimatelyencounterthepowerstationturbines.

UndertheenhancedschemethecapacityoftheexistingKaniereForksandMcKays

intakes and water races would be increased. Without adequate screening of the

intakeandtheprovisionofareturnflow,fishwillbeentrainedintothescheme.

6.2.3Turbinemortality

Downstream migrating fish that enter the water races will, without adequate

screening, be drawn through the power station turbines. Fish mortality due to

turbines has been well documented; as have results from impact (or ‘strike’),

pressure changes (associatedwith passing throughhigh, then low pressure zones

acrosstherunner)andhighshearstresses(closetofixedandmovingsurfacesand

intheturbulentwakeofthebladeandinthedrafttube)(Turnpennyetal.2000).It

ispossibletoestimatefishmortalityduringpassagethroughturbinesusingvarious

formulae(e.g.,Larinier&Travade1999;Turnpennyetal.2000)andinformationon

turbinedesign.Boubée(2003)estimatedsalmonidandeelmortalityduringpassage

through turbines for Project Aqua (lower Waitaki River) based on relatively low

head (30m)Kaplanturbines.Heestimated themortalityfortroutfry(30mmlong)

to be 3–6% during each turbine transit. For fingerlings (115mm long) mortality

during turbinepassagewas estimated tobe5–7%. Incontrast, formigrant female

longfin eel (1150mm long) the mortality during passage through just one turbine

wasestimatedatabout55%.

PassagethroughtheexistingandproposedMcKaysCreekandKaniereForkspower

station turbines is therefore likely to result inmortality for some fish,particularly

forlargerindividuals,whichincludesthreatenednativefishspecies(e.g.,adulteels).

6.2.4 Instreambarriers

There arecurrently twostructures associatedwith the schemewithin theKaniere


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Rivermainstemandone structure inBlueBottle Creek thatmayhinder upstream

fishpassage.

Immediately downstream of the Blue Bottle Creek intake is a small weir

approximately 1m high, formed by the placement of boulders across the channel

(Figure 4.13). There is nominimum residual flow in the creekdownstreamof the

intake, while the median flow is 0.06 cumecs (Table 5.6.1 Palmer 2010). At the

intaketheminimumflowis0.002cumecsandthemedianflowis0.21cumecs(Table

5.6.1Palmer2010).Atlowflowsthereisthereforeverylittlewaterflowingoverthe

weiranditappearsthatonlyclimbingnativefishspecies(e.g.,eels,koaro,lamprey,

andredfinbullies)wouldbeabletopass,withpoorerclimbers(e.g.bluegillbullies

andtorrentfish)preventedfrompassing.However,existingfishdistributionrecords

andourrecentsurveyconfirmthatallofthenativefishpresentdownstreamofthe

intakeweir are also present upstream (including brown trout, bluegill and redfin

bully, koaro and longfin eels) and passage must therefore be possible at higher

flows.Densitiesofbluegillandredfinbulliesarehigherdownstreamoftheweirthan

upstream though, possibly indicating that passage is limited although not

completelyprevented.Thepresenceofaconcretefordinthelowerreachesmayalso

limitfishpassagesomewhat(Figure4.15).Therewillbenochangefromtheexisting

situationundertheenhancedscheme.

IntheKaniereRivermainstemtherearetwostructures thatmayhinderupstream

fishpassage:McKaysweir(Figures1.5and6.1),whichislocatedapproximately9km

upstreamoftheconfluenceoftheKaniereandHokitikaRivers,andtheLakeKaniere

outletcontrolstructure(Figure1.2),whichislocatedafurther7kmupstream.

McKaysweir isa lowconcreteweir,whichat typical flowsisovertopped.At lower

waterlevelsnowaterflowsovertheweirandthecurrentresidualflow(0.2cumecs)

ismaintained through an underwater notch on the true left side of theweir. The

drop fromthecrestof theweir to theriverdownstreamvariesdependingonhow

muchwater isspillingover theweir,buttypically rangesfrom0.5‐0.9m.When the

weir isspilling,upstreampassageshouldbepossiblefor largesalmonids(i.e. trout

and salmon) and climbing native fish species; however, poorer climbers may be

preventedfrompassing.


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Figure6.1 Left:McKaysweirspilling.Right:McKaysweirwithnospill.

There are two channels at the Lake Kaniere outlet (Figure 6.2). The true right

channelleadsdirectlytotheintakeandcontrolgatesfortheKanierewaterrace.The

control gatesareadjusted tomanipulate the flowpassingdown theKaniereRiver.

As the gates are adjusted from the top continuouspassage is available to the lake

provided that fish are able to swim upstream against the high water velocity

through the gates. The second channel has a concrete weir and control boards

betweentheriverandthelakeoutlet(Figure1.2).Dependingonthelakelevelthere

isadropofapproximately0.5mfromthelakeovertheweirandcontrolboardsinto

this channel (Figure 6.2, right).Lake level records indicate that under theexisting

situationthelakespillsover theconcreteweirgreater than40%ofthetime,more

so duringOctober to January (Palmer2010). As at theMcKaysweir this overflow

should allow upstream passage for fish species that are good climbers; however,

poorer climbers may be prevented from passing. At lower lake levels, however,

there is no surface discharge from the lake to the true left channel. Under the

existingschemethelakespillsforgreaterthan40%ofthetime.Undertheenhanced

scheme this will reduce to only 8% of the time (Table 6.2.1 Palmer 2010). This

reductioninspillwillreduceopportunitiesforupstreamfishpassagefromtheriver

tothelake.


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Figure6.2 Left: Two channels at the Lake Kaniere outlet. Right: Control boards andconcreteweiratLakeKaniereoutlettotrueleftchannel.

Whetherupstream fishpassage ispossibleat thecontrol structures in theKaniere

River is therefore dependent on the flows in the river (and over the structures)

duringtheupstreammigrationperiodforeachfishspecies.Historical flowrecords

can be examined to determine if flows during migration periods are sufficient to

allow upstream passage. Alternatively, the existing distribution of fish in the

catchmentcanbeexaminedtoassesshowexistingfishdistributionisrelatedtothe

presenceofthestructures.

To assist with understanding fish distribution FWFDB records for the catchment

havebeendividedintofourgroups(Table6.3):

1. BelowMcKaysweir.

2. McKaysweirupstreamtoLakeKaniereoutlet.

3. LakeKaniere.

4. LakeKanieretributaries.

AmapshowingthelocationoffishrecordswithintheKaniereRivercatchmenthas

alsobeenprepared(Figure2.2).


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Table6.3 Distribution of native and introduced fish species in the Kaniere Rivercatchment, based on FWFDB (wetlands and forest pools omitted) and ourFebruary 2010 sampling. Numbers indicate the number of FWFDB records forthespeciesandatickindicatesthatthespecieswasrecordedduringsamplinginFebruary2010.

Location Fish species

Below McKays weir

McKays weir upstream to Lake Kaniere

outlet

Lake Kaniere Lake Kaniere tributaries

Brown mudfish* Banded kokopu 5 2 2 Giant kokopu 7 5 4 Inanga 7 Koaro 32 2 10 Shortjaw kokopu 33 2 Galaxiid species 4 4 1 Bluegill bully 11 Common bully 10 5 7 Redfin bully 41 2 1 Bully species 1 Longfin eel 36 2 1 11 Shortfin eel 2 1 2 Eel species 8 3 Lamprey 2 Torrentfish 17 1 Brown trout 14 2 12 Rainbow trout 1 Trout species 3 Chinook salmon 1 1 Perch 6 Total # of species** 14 6 6 11

* confined to wetlands and forest pools ** total number of fish taxa identified to species level

It is apparent fromTable 6.3 andFigure 2.2 that a greater number of species are

found downstream of McKays weir than upstream. Three native fish species,

lamprey, inanga andbluegill bullies, have only been recorded belowMcKaysweir

(Table 6.3, Figure 2.2). Inanga rarely penetrate far inland so their absence from

upstreamareasmaynotbeduetothepresenceoftheweir,however,bluegillbullies

and lamprey could be expected further inland. Torrentfish are another native

speciesthatiscommonintributariesbelowtheweir,butonlyasingleindividualhas

beenrecordedupstreaminalaketributary(Figure2.2).Likewiseredfinbulliesare

commonbelow theweir, but appear to be less common above theweir, although

they were found in Butchers Creek upstream of the weir during our February

survey.

ShortjawkokopuhavebeenrecordedfromtributariesbelowMcKaysweirandalso


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fromButchersCreek(Figure2.2).Theyhavenotbeenfoundabovethe lakeoutlet,

however, shortjaw kokopu are cryptic and seldom abundant, and so they may be

presentbuthavegoneundetectedintheuppercatchment.

Five native species are found in reasonable numbers throughout the catchment

(Table6.3andFigure2.2).Longfinandshortfineels,koaroandbandedkokopuare

known to be excellent climbers so it is likely that they are able to negotiate the

structures in the Kaniere River mainstem. Common bullies and giant kokopu are

also foundbothdownstreamof theweirand inLakeKaniere;however, it appears

thatpopulationsofbothspeciesinthelakeareland‐locked.

To summarise, it appears that McKays weir is hindering upstream passage, and

thereforelimitingthedistribution,ofbluegillbullies,lampreyandtorrentfishinthe

middle and upper reaches of the Kaniere River catchment. Upstream passage of

commonbullyandgiantkokopuisalsohindered,butbothspecieshavedeveloped

land‐lockedpopulations in LakeKaniere. Redfinbulliesand shortjawkokopuhave

been recordedupstreamof theweir; however, it appears they are not present, or

presentonlyin lownumbers, in theuppercatchment.Undertheenhancedscheme

therewillbenochangetotheLakeKanierecontrolstructureandBlueBottleCreek

intake. The Lake Kaniere intake gateswill bemodified andminor changeswill be

madetoMcKaysweir,however,thesechangesareunlikelytoimprovefishpassage

and any existing effect of these structures on upstream passage will therefore

continueunlessmitigated.

6.2.5Flowreductionsandconnectivity

(i) KaniereRiver

TheenhancedschemewillresultinflowreductionsinsomesectionsoftheKaniere

Rivermainstem relative to the existing situation (although in other sections flows

willincrease)(Table6.1).Thismayaffectfishpassageintwoways:byreducingthe

averageriverflowandmakinginstreambarriersmoredifficulttonegotiateandby

reducingthefrequencyandmagnitudeoffreshesandfloods.

Aspreviouslynoted,manyof thefishspecies in theKaniereRiverarediadromous,

migratingtoandfromtheseatocompletetheirlifecycle.Thetimingofdownstream

spawning migrations for some native species (e.g., eels and shortjaw kokopu) is


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associated with floods or elevated flows (Charteris 2006). Sufficient flow is also

required during periods of upstream migration to ensure that connectivity is

maintained to allow upstream passage within the mainstem and also to access

tributaries.Thisisalsoimportantforbrowntrout,whichundertaketheirupstream

spawningmigrationduringautumnandwinter.

Themainupstreammigrationperiodformostdiadromousnativefishspeciesfound

intheKaniereRivercatchmentisspringandearlysummer(Table6.4).Existingfish

distribution records indicate that under the current operating regime longfin and

shortfineels,bandedkokopu,koaroandprobablytosomeextent shortjawkokopu

and redfin bullies are able to travel upstream in the river. Bluegill bullies and

torrentfishdonotappeartobeabletonegotiateMcKaysweir;however,thisismost

likelydueprimarilytotheirpoorclimbingabilityandchangesinflowareunlikelyto

improvepassage for these species.Downstreammigration is occurring for at least

one species inmostmonths of the year (Table 6.4).However, themain species of

concern is the longfin eel (a threatened species), which migrates downstream in

autumnanddoessoduringfreshesorfloods.

Flowsimulationshavebeenundertakentopredicthowflowsinseverallocationsin

the KaniereRiverwill changeunder the enhanced scheme relative to the existing

situation.Comparingflowsbetween theexistingandenhancedschemesduringthe

peak periods for upstream and downstream fish migration allows the potential

effectofflowchangesonfishpassagetobedetermined.


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Table6.4 Upstreamanddownstreammigrationperiodsof somenative fish species foundintheKaniereRivercatchment.AdaptedfromEnvironmentWaikato(2007).

Summer Autumn Winter Spring Species

D J F M A M J J A S O N Upstream

Lamprey (adult) Bluegill and redfin bully (juvenile) Common bully (juvenile) Banded kokopu (juvenile) Giant kokopu (juvenile) Shortjaw kokopu and koaro (juvenile)

Shortfin and longfin eels (juvenile) Torrentfish (juvenile)

Downstream Lamprey (juvenile) Bluegill bully (larvae) Common bully (larvae) Redfin bully (larvae) Banded kokopu (larvae) Giant kokopu (larvae) Koaro (larvae) Shortjaw kokopu (larvae) Longfin eel (adult) Shortfin eel (adult) Torrentfish (larvae)

Fromthe flowdistributions for theriver it isapparent that inmost reachesof the

river the enhanced scheme will result in reduced flows relative to the existing

situation (Figures 6.3 to 6.7). For example, under the existing scheme, flows less

than0.5cumecsoccurfor lessthan1%ofthetimeintheKaniereRiveratthelake

outlet (Figure 6.3). Such low flowswill increase to approximately 92% frequency

undertheenhancedscheme(Figure6.3).Thefrequencyofflowsbelow0.5cumecs

willbegreaterthan50%undertheenhancedschemedownstreamofMcKaysweir

(Figure 6.5).Under theexistingscheme, flowsbelow1cumecoccur for 4%of the

time in the Kaniere River downstream of the Kaniere Forks station discharge

(Figure6.6).Suchlowflowswillhaveafrequencyofapproximately66%underthe

enhanced scheme (Figure 6.6). In the same reach flows less than 0.5 cumecs will

occurfor27%ofthetimeundertheenhancedscheme(Figure6.6).


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Kaniere Simulations - Kaniere River at Lake Outflow (2002-2008)

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90 100

Percent time value exceeded

Flo

w (

m3/s

)

Flow (m3/s) at Lake Kaniere river outflow (Actual)

Flow (m3/s) at Lake Kaniere river outflow (W8M8K0)

Figure6.3 KaniereRiverflowdistributionatthelakeoutletundertheexisting(Actual)and

enhanced(W8M8K0)schemes(graphprovidedbyLenniePalmer,TPL).

Kaniere Simulations - Kaniere River at Wards Road (2002-2008)

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90 100


Flo

w (

m3/s

)

Flow (m3/s) at Kaniere at Wards flow (Actual)

Flow (m3/s) at Kaniere at Wards flow (W8M8K0)

Figure6.4 KaniereRiver flowdistributionatWardsRoadunder theexisting (Actual)and



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Kaniere Simulations - Kaniere River at Downstream McKays Weir (2002-2008)

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90 100


Flo

w (

m3/s

)

Flow (m3/s) at Kaniere at dsMkyWeir flow (Actual)

Flow (m3/s) at Kaniere at dsMkyWeir flow (W8M8K0)

Figure6.5 KaniereRiver flowdistributiondownstreamofMcKaysweirunder theexisting

(Actual)andenhanced(W8M8K0)schemes(graphprovidedbyLenniePalmer,TPL).

Kaniere Simulations - Kaniere River at downstream Kaniere Forks station

(2002-2008)

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90 100


Flo

w (

m3/s

)

Flow (m3/s) at Kaniere at dsKnf flow (Actual)

Flow (m3/s) at Kaniere at dsKnf flow (W8M8K0)

Figure6.6 KaniereRiver flowdistributiondownstreamofKaniereForksstationunderthe

existing(Actual)andenhanced(W8M8K0)schemes(graphprovidedbyLenniePalmer,TPL).


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Kaniere Simulations - Kaniere River at Downstream McKays Creek station

(2002-2008)

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90 100


Flo

w (

m3/s

)

Flow (m3/s) at Kaniere at dsMky flow (Actual)

Flow (m3/s) at Kaniere at dsMky flow (W8M8K0)

Figure6.7 KaniereRiverflowdistributiondownstreamofMcKaysCreekStationunderthe

existing(Actual)andenhanced(W8M8K0)schemes(graphprovidedbyLenniePalmer,TPL).

Asanexampleofhowfishpassagemaybeaffectedduringthemainnativeupstream

migration period, monthly median river flows are shown in Figure 6.8 for six

locationsintheKaniereRiverundertheenhancedscheme.ThemonthofNovember

isanupstreammigrationperiodforthemajorityofnativefishfoundintheKaniere

River catchment, including bluegill, common and redfin bullies, banded, giant and

shortjawkokopu, koaro, longfin and shortfin eels and torrentfish (Table 6.4). It is

apparent that a juvenile koaro migrating upstream in the Kaniere River in

Novemberwill experiencewidevariation in flows as it progresses fromthe lower

end of the scheme below the McKays Creek station discharge to the lake outlet

(Figures6.8).Incontrast,flowsinanunmodifiedriverwouldberelativelyconstant

asthekoaroprogressedupstream,withtheonlyvariationperhapsbeingadecrease

inflowupstreamduetofewertributaryinflows.

In general, the enhanced scheme will reduce flows and increase flow variation

between most river reaches relative to the existing situation (Table 6.1). For

example, the sequence of median flows that a juvenile koaro might currently

encounter as itmigrated upstream inNovemberwould be approximately 7.4, 2.4,


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1.1, 5.5, and 5.4 cumecs (Palmer 2010). Under the enhanced scheme this would

becomeapproximately9.6,0.7,0.3,7.9,and0.3cumecs(i.e.,medianflowreductions

inthreeoffivereaches)(Figure6.8).

Kaniere River at various locations - Median flows by month

(Wards8_McKay8 scenario) 2002-2008

0

1

2

3

4

5

6

7

8

9

10

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Flo

w (

m3/s

)

Downstream of lake Downstream of Wards rd

at McKays Weir total flow Downstream McKays Weir

Downstream of Kaniere Forks station Downstream of McKays Creek station

Figure6.8 Monthlymedian flow (cumecs) at six locations in theKaniereRiver under the

enhancedscheme(graphprovidedbyLenniePalmer,TPL).

The major flow variations between reaches are due to water intakes and water

discharges above and below power stations. A major variation in flow currently

occursupstreamanddownstreamof theMcKayspowerstationdischarge (median

flowvariation4.6cumecs),andthisvariationincreasesundertheenhancedscheme

(8.3 cumecs). As the discharge from theMcKays power station is currently larger

than the median flow in the river mainstem upstream, migrating fish may be

encouragedtocontinueupthedischargechanneltowardsthepowerstationduring

generationratherthanuptherivermainstem.Thiseffectislikelytobeexacerbated

under the enhanced scheme. The discharge from the proposed new Wards Road

station would also exceed median flows in the river mainstem so upstream

migratingfish,unlesspreventedfromdoingso,mayalsoenterthestationtailraces

duringgeneration.

Asidefromupstreammigratingfishpotentiallybeingattractedtothepowerstation


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tailraces during generation, reductions in flowmay also affect connectivitywithin

themainstemandaccess to tributaries. Inordertoallowidentificationofareasin

theriverwherethismaybeaproblemTPLreducedflowsatthelakeoutlet(within

existing consent conditions) to 0.2 cumecs on 26May2010. The flow in the river

wassupplementeddownstreamofherebysurfaceinflowssuchthat,atWardsRoad,

theflowhadincreasedto0.65cumecs.Ourinspectionsoftheriveratseveralpoints

at this flowdid not identify any connectivity issues. A similar flow reduction trial

wasundertakenin thelowerriveron11August2010.DischargefromtheKaniere

ForkspowerstationwasstoppedandflowintheriverdownstreamofMcKaysweir

wasmaintainedat0.22cumecs.Thisresultedinaflowofapproximately0.8cumecs

at McKays Ford, flows increased downstream with tributary inflows. The entire

river reach fromMcKays weir downstream to the McKays power station tailrace

discharge (approximately 3.8km long)was inspectedunder these flow conditions.

Several sections were identified where maximum water depths at these flows

rangedfrom20‐30cm(e.g.Figure6.9).Thelengthoftheseshallowsectionsranged

fromonly1‐2mtogreaterthan10m.Nativefishpassageisunlikelytobeaffectedby

theshallowwaterdepthsobserved,however,passagefor largersalmonidsmaybe.

Flows insomereaches under theenhanced schemewould alsobe lower than that

whichwasobservedon11August(e.g.0.50not0.8cumecsatMcKaysFord).


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Figure6.9 Kaniere River below McKays weir to McKays Ford (left to right, upstream todownstream) at flows of approximately 0.22 cumecs (top photos) and 0.8 cumecs(bottomphotos).Undertheenhancedschemetheminimumflowthroughoutthisreachwouldrangefrom0.3to0.5cumecs.

Mayand Juneare likely tobe importantmonths fordownstream fishmigration in

the Kaniere River, as it is during these months that adult longfin eels and larval

galaxiids migrate downstream (Table 6.4), although this can be dependent on a

numberofenvironmentalvariablessuchasrainfallandtemperature(Ryder2006).

Downstreameelmigration typicallypeaksduringperiodsofelevatedflowsoasan

example maximum flows during May and June were therefore examined for the

enhancedscheme(Figure6.10).InMaymaximumflowinthereachdownstreamof

thelakeoutletisonly0.39cumecs.Thisisdueto8cumecsbeingtakenintothenew

Wards Road race at the lake outlet. Freshes and floods above 8 cumecs will,

however,passdowntheriver,asobservedinJune(Figure6.10),andasdownstream

migrating eelsmost likely take their cue tomigrate from increased inflows to the

lake it is possible that operation of the scheme will not affect the cue for


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downstreammigration.FlowsimulationsindicatethatdailyinflowstoLakeKaniere

exceed8cumecsapproximately27%ofthetimeinMayand40%ofthetimeinJune

(Figure5.2.7Palmer2010).

Figure6.10 Simulated3hourlymaximumflows(cumecs)intheKaniereRiver,MayandJune

20022008undertheenhancedscheme.

(ii) BlueBottleCreek

Theexisting take fromBlueBottle Creek to theMcKaysrace is up to1cumec and

thiswillnotchangeundertheenhancedscheme.ThemedianflowattheBlueBottle

Creek intake is 0.21 cumecs (Table 5.6.1 Palmer 2010). The intake captures

approximately 80‐90%of the flow inBlueBottle Creekat flowsbelow0.5 cumecs

and approximately 20% at flows above 1 cumec (Palmer 2010). No minimum

residual flow is provided below the intake in Blue Bottle Creek and the median

residual flow is 0.06 cumecs (Palmer 2010). Under low flow conditions the creek

channelhasbeenobservedtohavenosurfaceflowforatleast100mdownstreamof

theintake(V.Keesing,pers.comm.).Furtherdownstream,surfaceandgroundwater

inflows contribute water so there is surface flow, although connectivity is limited

under these conditions. Despite this existing situation, fish distribution records

indicate that fish can and do move freely throughout the creek at higher flows,

although fish densities indicate instream structures may limit this movement

somewhat(refertoSection6.2.4).


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6.3 Waterquality

6.3.1Background

Water quality in the Kaniere River is good due to the limited development in the

catchment and the large amount of native riparian vegetation that remains as a

consequenceofthis.Therearenomajordischargestotheriversoreducedflowsin

theriverunder the enhanced schemewillhavenoeffectonpotential contaminant

dilutions,however,watertemperaturesmaybeaffected.

6.3.2Watertemperature

Amaximumwater temperature of 23°Cwas recorded in the Kaniere River during

monitoring fromNovember to April this year. Sustained periods of reduced flow

under the enhanced scheme could cause temperature variation in the river,

particularly during summer months. Substantial increases in water temperature

coupledwith an absence of safe retreats can result in fish and invertebrate stress

and potential mortality. While flow does not have a large effect on daily mean

temperatures, a reduction in flow will increase diurnal variation by increasing

temperaturesintheafternoonanddecreasingtheminearlymorning.Anincreasein

diurnal maximum temperatures has less effect on aquatic invertebrates than the

samechangeindailymeantemperature(CoxandRutherford2000).

Thereisdetailedinformationavailableontheeffectsofwatertemperatureonriver

invertebrates. Water temperature can affect abundance, growth, metabolism,

reproduction, and activity levels of aquatic insects. A detailed analysis of 88 New

Zealandrivers(QuinnandHickey1990)identifiedwatertemperatureasoneofthe

important variables affecting species distribution. Stoneflies (Plecoptera) were

largelyconfinedtoriversbetween13and19°C,andmayflies(Ephemeroptera)were

lesscommon in riverswithmaximum temperaturesof>21.5°C (QuinnandHickey

1990).ThecommonmayflyDeleatidiumhasanLT50(thetemperatureatwhich50%

ofindividualswilldie)of22.6°C(Table6.5).


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Table6.5 Upper lethal temperatures (based on an LT50 standard, the temperature atwhich50%ofindividualswilldie)forthecommoninvertebratetaxa.

Taxa Life stage Upper lethal

temperature (°C) Source

Deleatidium spp. Mid-late instar 22.6-26.8 Quinn et al. 1994 Cox & Rutherford 2000

Aoteapsyche spp. Mid-late instar 25.9-27.8 Quinn et al. 1994 Elmidae Mid-late instar 32.6-34.0 Quinn et al. 1994 Potamopyrgus antipodarum Unknown 31.0 Cox and Rutherford 2000 Zelandobius spp. Mid-late instar 28.0 Quinn et al. 1994

There is the potential at high temperatures forDeleatidium to be replaced by the

grazing snail Potamopyrgus antipodarum, which has a much higher LT50 (31.0°C).

Potamopyrgus canbeconsidereda lessdesirable taxaas it isa lessattractiveprey

itemfortroutandnativefish.SomerecentresearchhassuggestedthatDeleatidium

may be able to survive short periods of high temperatures, provided they have

experienced a summer acclimation period (Cox and Rutherford 2000). There are

already some existing differences in the invertebrate community of the Kaniere

River among sites, with Potamopyrgus snails more common than Deleatidium

mayfliesatsitesupstreamofMcKaysweir,andtheoppositepatterndownstreamof

McKays weir (refer to Section 4.1.4). Due to the limited amount of water

temperaturedataavailableitisnotpossibletodeterminefromexistinginformation

if this is due to water temperature differences among sites or to greater flow

stabilityandperiphytonaccrualassociatedwiththelakeoutlet.

TheeffectsofwatertemperatureonNewZealandnativefishhavebeensummarised

by Richardson et al. (1994). In general the tolerances for native fish species are

muchhigherthanfortrout(Table6.6),andlethaltemperaturesareunlikelytoever

beachievedinflowingsectionsofmostrivers.Trout, therefore,remain thespecies

that if protected against temperature increases will result in protection of other

riverfishspecies.

The effect of the flow reduction on water temperatures in rivers is typically

predicted using the WAIORA model (Jowett et al. 2004). However, as under the

enhanced scheme flowswillvarymarkedly indifferent locations in theriveroften

overshortdistances(e.g.2km),dependingonhowmuchwaterisbeingdiverted,the

WAIORAmodelisdifficulttoapply.


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Surfacewatertemperatureisdrivenbyclimaticandgeographicconditionsincluding

airtemperature,radiationandshade.ThehighwatertemperaturesinKaniereRiver

inlatesummeraredrivenbythelakeoutletwatertemperatureaslakesactasheat

stores.TheArnoldRiver,whichflowsoutofLakeBrunner,isagoodexampleofthis

ontheWestCoast(seeJowett2010;Ryder2010).However,whentheflowofariver

reduces it becomes more sensitive to radiation because it is shallower and flows

moreslowly.Asaresultofdayheatingandnightcooling,dailyfluctuationsinwater

temperatureincrease,butthereislittlechangeinthedailymeantemperature.

Table6.6 Upper lethal temperatures (based on an LT50 standard, the temperature at

which50%ofindividualswilldie)andpreferredtemperaturesforarangeoffishspecies.Superscriptsmatchtemperaturevaluestothereferencesource.

Species Life stage Upper lethal temperature

Preferred temp (and quartiles)

Source

Short-finned eel (Anguilla australis)

Elver Adult

35.71

39.71 26.9 (25.6-28.5)1

26.02 1Richardson et al. 1994

2Todd 1981 Long-finned eel (A. dieffenbachii)

Elver Adult

34.81 37.31

24.4 (22.6-26.2)1 24.02

1Richardson et al. 1994 2Todd 1981

Common bully (Gobiomorphus cotidianus)

All 30.9 20.2 (18.7-21.8) Richardson et al. 1994

Torrentfish (Cheimarricthys fosteri)

Adult 30.0 21.8 (20.1-22.9) Richardson et al. 1994

Inanga (Galaxias maculatus)

Juvenile Adult

33.11 30.82

18.7 (17.2-20.0)2

18.1 (17.2-19.1)2 1Simons 1986

2Richardson et al. 1994 Common smelt (Retropinna retropinna)

Adult 28.3 16.1 (15.1-17.4) Richardson et al. 1994

Brown trout (Salmo trutta) Adult

Juvenile

24.71

29.62 17.4-17.63

13-141

1Elliott 1994 2Elliott and Elliott 1995

3Collier et al. 1995 Quinnat salmon (Oncorhynchus tshawytscha)

Adult

Juvenile

21.01 25.12 25.01

11.3-13.31 14.81

12-133

1Armour 1991 2Elliott 1994

3McCollough 1999

6.4 Instreamhabitat

6.4.1Background

Therelationshipbetween instreamhabitatand flow forkey aquatic species in the

Kaniere Riverwas estimated with habitat hydraulicmapping using instream flow

incrementalmethodology(IFIM).Thisapproachenablesanassessmenttobemade

of the effects of flow alterations on physical habitat for fish, invertebrates and

periphyton.


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Tworeachesoftheriverweresurveyed:anupperreach(WardsRoad,Figure6.11)

representingthenarrower,steepergradientsectionoftheriverfromthelakeoutlet

to upstream of McKays weir, and a lower reach (McKays Ford, Figure 6.12)

representingthewiderandlesssteepsectiondownstreamofMcKaysweir.

Figure6.11 WardsRoadinstreamhabitatassessmentreach,flow1.1cumecs.

Figure6.12 McKaysFordinstreamhabitatassessmentreach,flow1.5cumecs.

The two components of an IFIM analysis are the hydraulic simulations of a stream reach

and habitat suitability criteria for the taxa of interest (e.g. fish, macroinvertebrates, and

periphyton). Hydraulic simulation is used to describe the area of a stream having various

combinations of depth, velocity and substrate type as a function of flow. This information

is used to calculate the Weighted Useable Area (WUA) of the stream segment from

suitability information based on field sampling of various aquatic species. Habitat

suitability criteria are a way of describing what is considered to be ‘good’ habitat (Jowett

1996). Once habitat suitability criteria are defined they can be applied to habitat survey


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data and the amount of suitable habitat with varying flow calculated.

Habitat suitability was modelled against flow using RHYHABSIM software (River

HydraulicsandHabitatSimulation, Jowett1996). References forhabitat suitability

criteria are given in Table 6.7. Nine fish species and five macroinvertebrate taxa

wereincludedinthemodel.Foodproducinghabitat,whichbrowntroutabundance

is related to (Jowett1992),was alsomodelled.Threeperiphyton groups:diatoms,

and short and long filamentous algae,were included to evaluate the potential for

nuisancealgaegrowths.

Table6.7 Habitat suitability criteria used for the Kaniere River instream habitatassessment.

Species/life stage Reference

Native fish

Bluegill bully Jowett and Richardson 2008

Common bully Jowett and Richardson 2008

Redfin bully Jowett and Richardson 2008

Koaro Jowett and Richardson 2008

Shortjaw kokopu McDowall et al. 1996

Longfin eel (<300mm and >300mm) Jowett and Richardson 2008

Shortfin eel (<300mm and >300mm) Jowett and Richardson 2008

Torrentfish Jowett and Richardson 2008

Trout

Brown trout, <100mm Jowett and Richardson 2008

Brown trout, adult Hayes and Jowett 1994

Food producing habitat Waters 1976

Macroinvertebrates

Aoteapsyche species Jowett et al. 1991

Deleatidium species Jowett et al. 1991

Elmidae Jowett et al. 2003

Orthocladiinae Jowett et al. 2003

Potamopyrgus species Jowett et al. 2003

Periphyton

Diatoms Rhyhabsim v5.0

Long filamentous Rhyhabsim v5.0

Short filamentous Rhyhabsim v5.0


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Representative cross-sections for hydraulic measurements were randomly chosen within

each of the three general habitat types: pool, run, and riffle. Twelve cross-sections were

surveyed at each reach, with the number of cross-sections within each habitat type

calculated according to the proportion of each habitat type within the reach. This was

determined by general visual assessment of the river habitat and detailed measurement of

the amount of each habitat within an approximate 1km reach.

Cross-sections were marked across the river using a level line strung between survey

pegs. To allow measurement of the degree of water level variation at each cross-section

with flow a steel water-level gauging rod was hammered into the riverbed or alternatively

a point was marked on the river edge. Water velocity, depth and bed substrate-type was

measured at a series of points across the river (approximately every 0.5-1m), and bank

profile was described to a height of approximately 1m above the water level.

Survey and calibration flows for each reach are shown in Table 6.8. Water level and

hydraulic measurements were made at each cross-section at the survey flow. At the two

(McKays Ford) or three (Wards Road) calibration flows water levelwasmeasuredat

eachcross‐sectionandthedischargeatarepresentativecross‐sectiondetermined.

Table6.8 Survey and calibration flows for theWardsRoad andMcKays Ford IFIM sites.‘NA’=notapplicable.

Wards Road flow (cumecs)

McKays Ford flow (cumecs)

Survey flow 1.1 1.5

Calibration flow 1 3.3 2.4

Calibration flow 2 5.5 2.1

Calibration flow 3 0.7 NA

6.4.2Proposedminimumflows

Undertheenhancedschemeflowswillvaryindifferentlocationsintheriver(Table

6.1).TheWardsRoadIFIMmodelcanbeusedtopredictavailableinstreamhabitat

foraquatictaxaat locationsupstreamofMcKaysweirundertheseflowconditions,

and the McKays Road IFIM is representative of locations downstream of McKays

weir.


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(i) Physicalcharacteristics

Mean water depth, velocity and channel and wetted perimeter width generally

increasedgraduallywithincreasingflowinbothsurveyreachesintheKaniereRiver

(Figures6.15and6.16).Asexpected,watervelocitiesarehigherandincreasemore

quicklywithincreasingflowattheWardsRoadsiterelativetotheMcKaysFordsite,

reflectingthedifferenceinthechannelgradientbetweenthesites(Figures6.13and

6.14). Channelandwettedperimeterwidths arealso narrowerat theWardsRoad

site(Figures6.13and6.14).

Figure6.13 Variation of average velocity, depth,width andwetted perimeterwith flow in

theKaniereRiverWardsRoadIFIMreach.


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Figure6.14 Variation of average velocity, depth,width andwetted perimeterwith flow in

theKaniereRiverMcKaysFordIFIMreach.

Mean physical characteristics at five locations in the Kaniere River at predicted

minimumandmedianflowsundertheexistingsituationand theenhancedscheme

are shown in Tables 6.9 and 6.10. Water depth and velocity are particularly

important characteristics of the river as any changes may affect the quantity and

qualityof instreamhabitat foraquaticcommunities.Changesinchannelwidthand

wettedperimeteralsoaffectthequantityofavailableinstreamhabitat.

IntheriverupstreamofMcKaysweir (i.e. sites ‘downstreamof lakeoutlet’ and ‘at

WardsRoad’),theenhancedschemewillresultinreductionsinmeanwatervelocity,

depth, width and wetted perimeter relative to the existing situation (Table 6.9).

Velocitieswillbe reducedby approximately41‐48%anddepthsby approximately

25‐30% (Table 6.9). Channel width and wetted perimeter will be reduced by

approximately0.9‐1.2m(Table6.9).Attwoofthethreeriverreachesdownstreamof


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McKays weir (‘downstream of McKays weir’ and ‘downstream of Kaniere Forks

station’)meanwatervelocities,depthandwidthsunder theenhancedschemewill

beslightlyhigherthantheexistingminimumflowsituation(Table6.9).Downstream

ofMcKaysCreek station,meanvelocities,depthsandwidthswillbe slightly lower

thantheexistingsituation(Table6.9).

Table6.9 Mean physical characteristics at the minimum flow as predicted from therelevant IFIM model (Wards Road or McKays Ford) at five locations in theKaniereRiverundertheexistingsituationandtheenhancedscheme.

Operating regime

Physical characteristic


2. At Wards

Road Station


weir


Forks Station


Creek Station

Existing Minimum flow (cumecs) 0.92 1.0 0.20 0.26 0.82

Velocity (m/s) 0.31 0.32 0.07 0.07 0.17 Depth (m) 0.27 0.28 0.23 0.24 0.28 Width (m) 10.6 10.7 12.9 12.9 16.0

Wetted perimeter (m) 10.9 11.0 13.0 13.0 16.1

Enhanced Minimum flow (cumecs) 0.30 0.40 0.30 0.38 0.74

Velocity (m/s) 0.16 0.19 0.09 0.10 0.16

Depth (m) 0.19 0.21 0.25 0.26 0.27

Width (m) 9.5 9.8 13.5 14.0 15.5


Atmedian flows the enhanced schemeresults in reductions invelocity,depth and

widthatthreeofthefivelocationsrelativetotheexistingsituation:‘downstreamof

lake outlet’, ‘downstream of McKays weir’, and ‘downstream of Kaniere Forks

Station’(Table6.10).Attheremainingtwosites, ‘atWardsRoad’and ‘downstream

ofMcKays Creek Station’ the enhanced schemewould result in slightly increased

velocities,depthsandwidthsatthemedianflow(Table6.10).

Differences in the physical characteristics of the riverunder the enhancedscheme

will result in differences in the available instream habitat for aquatic taxa at each

location depending on their particular habitat requirements, as discussed in the

followingsections.


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Table6.10 MeanphysicalcharacteristicsatthemedianflowaspredictedfromtherelevantIFIMmodel(WardsRoadorMcKaysFord)atfivelocationsintheKaniereRiverundertheexistingsituationandtheenhancedscheme.

Operating regime

Physical characteristic


2. At Wards

Road Station


weir


Forks Station


Creek Station

Existing Median flow (cumecs) 5.5 5.8 1.4 2.9 7.5

Velocity (m/s) 0.88 0.90 0.25 0.41 0.78 Depth (m) 0.49 0.50 0.30 0.34 0.40 Width (m) 12.3 12.3 16.7 17.9 20.0


Enhanced Median flow (cumecs) 0.33 7.9 0.30 0.68 9.0

Velocity (m/s) 0.16 1.1 0.09 0.16 0.89

Depth (m) 0.19 0.55 0.25 0.27 0.41

Width (m) 9.5 12.6 13.5 15.5 20.5



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(ii) Instreamhabitat

There are twomeasures of instream habitat that can be used to assess minimum

flowrequirementsofaquatictaxa.WUA(m2/m,WUA)canberegardedasameasure

ofthequantityofpotentiallyavailablehabitatprovidedbytheflow,andtheaverage

habitat suitability index (HSI) is a measure of the quality of the habitat. HSI is

numerically equivalent to WUA divided by the wetted river width (Jowett et al.

2008). Both measures of instream habitat are presented below for fish,

invertebrates,macrophytesandperiphytonatthetwoIFIMlocationsintheKaniere

River.

1. WardsRoad

Nativefish

Available habitat for eight native fish species (bluegill bully, commonbully, redfin

bully, koaro, shortjawed kokopu, longfin eel, shortfin eel and torrentfish) was

modelled.Habitatformostnativefishspeciesismaximisedatflowsbelow1cumec;

however,habitat forbluegillbully,koaroand torrentfish isgreaterathigher flows

duetotheirhighervelocitypreferences(Figure6.15).


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Figure6.15 Variation of WUA (m2/m) and HSI with flow for bluegill bully, common bully,

redfinbully, koaro, shortjawedkokopu, longfinand shortfineels (<300mmand>300mm)andtorrentfishintheKaniereRiveratWardsRoad.


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Browntrout

Habitat foradultbrown troutandfoodproducingismaximisedat flowsof2.7and

3.7cumecsrespectivelyattheWardsRoadIFIMreach (Figure6.16).Smaller trout

(<100mm)havelowerflowrequirementsandtheirhabitatismaximisedatflowsof

around1cumec(Figure6.16).

Figure6.16 VariationofWUA(m2/m)andHSIwithflowforbrowntroutandfoodproducing

habitatintheKaniereRiveratWardsRoad.

Benthicmacroinvertebrates

Available habitat for the five macroinvertebrate taxa modelled show differing

responses to decreasing flow (Figure 6.17). Both the quantity (WUA) and quality

(HSI)ofhabitatincreasesforElmidae(beetles)andPotamopyrgusspecies(snail)as

flowsdecrease;however,forAoteapsyche(netspinningcaddisfly)habitatimproves

as flows increases (Figure 6.17). Habitat forDeleatidiummayflies ismaximised at


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2.8cumecs(Figure6.17).

Figure6.17 VariationofWUA(m2/m)andHSIwithflowforfivebenthicmacroinvertebrate

taxaintheKaniereRiveratWardsRoad.

Periphyton

Thegrowthoflongfilamentousalgaeinarivercanresultinchangestoinvertebrate

communities and in the availability of invertebrates as food for fish. As flows

decrease in the river, the amount of potential habitat for both short and long

filamentousalgaeincreases(Figure6.18).Thequantity (WUA)andquality(HSI)of

habitatforlongfilamentousalgaeishighatflowsof0.2‐0.4cumecs(Figure6.18).In

contrast, as flows decrease the habitat becomes less suitable for diatoms (Figure

6.18).


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Figure6.18 VariationofWUA(m2/m)andHSIwithflowforperiphyton(diatoms,shortand

longfilamentousalgae)intheKaniereRiveratWardsRoad.

2. McKaysFord

Nativefish

Available habitat for eight native fish species (bluegill bully, commonbully, redfin

bully, koaro, shortjawed kokopu, longfin eel, shortfin eel and torrentfish) was

modelled.Habitat formostnativefishspecies ismaximisedat flowsbetween0.5‐2

cumecs;however,habitatforbluegillbully,koaroandtorrentfishisgreaterathigher

flowsduetotheirhighervelocitypreferences(Figure6.19).


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Figure6.19 Variation of WUA (m2/m) and HSI with flow for bluegill bully, common bully,redfinbully, koaro, shortjawedkokopu, longfinand shortfineels (<300mmand>300mm)andtorrentfishintheKaniereRiveratMcKaysFord.

Browntrout

Habitat foradultbrown troutandfoodproducingismaximisedat flowsof2.5and

3.7cumecsrespectivelyattheWardsRoadIFIMreach (Figure6.20).Smaller trout

(<100mm) have lower flow requirements with habitat maximised at flows of 2.3

cumecs(Figure6.20).


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Figure6.20 VariationofWUA(m2/m)andHSIwithflowforbrowntroutandfoodproducing

habitatintheKaniereRiveratMcKaysFord.

Benthicmacroinvertebrates

Available habitat for the five macroinvertebrate taxa modelled show differing

responses to decreasing flow (Figure 6.21). Both the quantity (WUA) and quality

(HSI) ofhabitat increases forElmidae (beetles) andPotamopyrgus (snail)as flows

decrease; however, for Aoteapsyche (net spinning caddisfly) habitat improves as

flows increases (Figure 6.21). Habitat for Deleatidium mayflies is maximised at 5

cumecs(Figure6.21).


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Figure6.21 VariationofWUA(m2/m)andHSIwithflowforfivebenthicmacroinvertebratetaxaintheKaniereRiveratMcKaysFord.

Periphyton

Thegrowthoflongfilamentousalgaeinarivercanresultinchangestoinvertebrate

communities and in the availability of invertebrates as food for fish. As flows

decrease in the river, the amount of potential habitat for both short and long

filamentousalgaeincreases(Figure6.22).Thequantity (WUA)andquality(HSI)of

habitatfor longfilamentousalgaeishighatflowsaround0.7cumecs(Figure6.22).

Incontrast,asflowsdecreasethehabitatbecomeslesssuitablefordiatoms(Figure

6.22).


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Figure6.22 VariationofWUA(m2/m)andHSIwithflowforperiphyton(diatoms,shortand

longfilamentousalgae)intheKaniereRiveratMcKaysFord.

3. Instreamhabitatquantitysummary

The amount of available instream habitat (WUA) for aquatic species under the

existingsituationandenhancedschemeisshownforeachofthefivelocationsinthe

riverinTables6.11‐6.15.Theapproximatelengthofriverrelatingtoeachlocationis

asfollows:

• Lakeoutlet–3.1km;

• WardsRoad–4.1km;

• DownstreamofMcKaysweir–1.8km;

• DownstreamofKaniereForksStation–2.0km;and

• DownstreamofMcKaysCreekStation–5.6km.

Theamountofhabitatavailablefora speciesdependsonitshabitatrequirements,


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for some species theamountofhabitat increases as flows increase (e.g.koaro and

torrentfish)andforotherspeciesitdecreases(e.g.commonbullyandredfinbully).

Habitat requirements dependon themanagement objectives of the river, and it is

fair to say that to date the Kaniere River has been managed primarily for hydro

generation. However, the river also provides habitat for native fish species and

consideration is required toprovide sufficient flow to sustain their populationsas

wellasprovidingsomehabitatforotheraquatictaxa(e.g.,browntroutandbenthic

invertebrates) andminimising nuisance algae growths. The amount of habitat for

aquatic taxa under the enhanced scheme relative to the existing situation at

minimum and median flows is discussed below (progressing from upstream to

downstream).

Under the enhancedscheme,minimum flows in the twoupstream locations (i.e. at

‘lakeoutlet’and‘WardsRoad’)willbereducedbyapproximately57‐67%relativeto

the existing situation and as a result habitat formost native fish (except common

bully,redfinbully,shortjawkokopuandshortfineel(<300mm)),browntrout,food

producinghabitatand invertebrates in theriver isgenerallypredicted todecrease

(Tables6.11and6.12). Incontrast, although themedian flowwouldbereducedat

the lake outlet by approximately 94% relative to the existing situation, due to the

physical characteristics of the river here, a median flow reduction is actually

predicted to increase habitat formost native fish species (Table 6.10). Habitat for

native fish species with higher velocity preferences (bluegill bully, koaro, and

torrentfish), adult brown trout, food producing habitat and most invertebrates is,

however,predictedtoreduce(Table6.11).

AtWardsRoadtheproposedmedianflowisapproximately2cumecshigherthanthe

existing median flow (Table 6.12). Due to the physical characteristics of the river

thiswillresult inareductioninhabitat forall fishspecies, foodproducinghabitat,

andmostinvertebratespecies(Table6.12).

InthereachdownstreamofMcKaysweir,theminimumflowof0.3cumecsisslightly

higher than the existing situation (Table 6.13). This will result in similar or

increased habitat for all fish species, food producing habitat, and invertebrate

species relative to the existingsituation (Table 6.13).However, themedian flow is

alsoapproximately 0.3 cumecs,which is approximately1.1cumecs lower than the


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existing median flow, resulting in predicted habitat reductions for most species

(Table6.13).

Minimumflowsinthevicinityof ‘downstreamofKaniereForks’areapproximately

0.12 cumecs higher than the existing situation, resulting in slightly increased

habitat,however,medianflowsarelower(Table6.14).Decreasedmedianflowswill

increasehabitatforsomenativefishspecies,althoughhabitatfornativefishspecies

with higher velocity preferences, adult brown trout, food producing habitat and

mostinvertebrateswillreduce(Table6.14).

Atthemostdownstreamlocation,minimumflowsarereducedbyapproximately0.1

cumecsrelativetotheexistingsituationwithhabitatformostnativefish,trout,food

producinghabitatandinvertebratespredictedtobesimilarorslightlyreducedasa

result (Table6.15).Median flowsare increasedbyapproximately 1.5cumecswith

habitat for most native fish, trout, food producing habitat and invertebrates

predictedtobesimilarorslightlyreducedasaresult(Table6.15).

In conclusion, relative to the existing situation upstream of McKays weir (reach

lengthapproximately7.2km),theproposeddecreasedminimumflowsarepredicted

to decrease habitat for native fish, brown trout, food producing habitat and

invertebrates. Reducedmedian flows at the lake outletwould increase habitat for

nativefishspecieswith lowvelocitypreferences,however, increasedmedian flows

atWardsRoadwoulddecreasehabitat.

In the reach downstream of McKays weir (length approximately 1.8km) the

proposedminimumflowistheslightlyhigherthantheexistingsituationresultingin

similarorslightlyincreasedhabitat.However,theproposeddecreasedmedianflow

ispredictedtodecreasehabitatformostspecies.

In the reach downstream of Kaniere Forks station (length approximately 2km)

proposedminimum flows are predicted to slightly increase habitat for native fish,

trout, food producing habitat and invertebrates relative to the existing situation.

However,proposeddecreasedmedianflowsarepredictedtodecreasehabitatforall

speciesexceptthosewithlowervelocitypreferences.


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In the reach downstream of McKays Creek station (length approximately 5.6km)

proposeddecreasedminimumandincreasedmedianflowsarepredictedtoincrease

habitatfornativefishspecieswithlowvelocitypreferences,relativetotheexisting

situation.

Inmost reacheshabitat fornuisance long filamentousalgaegrowthsarepredicted

to be similar or increased under the enhanced scheme relative to the existing

situation.


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Table6.11 Physical habitat expressed as WUA (m2/m) for a range of species at theminimum and median flows (cumecs) in the Kaniere River at the lake outletunder the existing situation and the enhanced scheme. Predicted using theWardsRoadIFIMmodel.

Operating regime Existing Enhanced Existing Enhanced

Minimum flow (cumecs) Median flow (cumecs)

0.92 0.3 5.5 0.33

Native fish

Bluegill bully 2.3 0.4 1.4 0.4

Common bully 7.5 7.8 0.9 7.8

Redfin bully 7.0 6.8 1.3 6.8

Koaro 2.7 1.5 1.9 1.5

Shortjaw kokopu 0.4 1.4 0.0 1.4

Longfin eel (<300mm) 6.8 5.0 3.0 5.0

Longfin eel (>300mm) 4.0 1.8 0.3 1.8

Shortfin eel (<300mm) 8.5 7.9 1.9 7.9

Shortfin eel (>300mm) 4.3 2.8 0.2 2.8

Torrentfish 1.3 0.0 3.4 0.0

Trout

Brown trout, <100mm 5.3 3.9 2.7 3.9

Brown trout, adult 1.2 0.2 1.1 0.2

Food producing habitat 4.2 1.1 7.2 1.1

Macroinvertebrates

Aoteapsyche species 0.4 0.2 5.1 0.2

Deleatidium species 5.9 4.0 6.5 4.0

Elmidae 5.0 5.2 2.9 5.2

Orthocladiinae 7.2 4.3 9.3 4.3

Potamopyrgus species 4.8 4.1 2.6 4.1

Periphyton

Diatoms 0.0 0.0 9.4 0.0

Long filamentous 6.7 8.9 0.6 8.9

Short filamentous 5.1 0.6 4.6 0.6


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Table6.12 WUA(m2/m)forarangeofspeciesattheminimumandmedianflows(cumecs)in the Kaniere River at Wards Road under the existing situation and theenhancedscheme.PredictedusingtheWardsRoadIFIMmodel.



0.95 0.4 5.8 7.9

Native fish


Common bully 7.1 8.2 0.9 0.6

Redfin bully 6.7 7.2 1.2 0.7

Koaro 2.8 1.8 1.8 1.3


Longfin eel (<300mm) 6.8 5.7 2.8 1.9

Longfin eel (>300mm) 4.1 2.3 0.3 0.1

Shortfin eel (<300mm) 8.4 8.3 1.7 1.2

Shortfin eel (>300mm) 4.3 3.4 0.2 0.1


Trout

Brown trout, <100mm 5.3 4.5 2.6 2.0



Macroinvertebrates



Elmidae 4.9 5.2 2.8 2.3



Periphyton

Diatoms 0.0 0.0 9.4 9.4




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Table6.13 WUA(m2/m)forarangeofspeciesattheminimumandmedianflows(cumecs)in the Kaniere River downstream ofMcKaysweir under the existing situationandtheenhancedscheme.PredictedusingtheMcKaysFordIFIMmodel.



0.20 0.30 1.4 0.31

Native fish


Common bully 7.9 8.9 9.8 8.9

Redfin bully 5.7 6.5 8.2 6.5

Koaro 0.7 0.9 2.5 0.9


Longfin eel (<300mm) 3.4 4.0 7.6 4.0

Longfin eel (>300mm) 3.5 4.2 6.1 4.2

Shortfin eel (<300mm) 7.4 8.2 9.9 8.2

Shortfin eel (>300mm) 4.2 4.8 5.9 4.8


Trout

Brown trout, <100mm 2.1 2.8 5.7 2.8



Macroinvertebrates



Elmidae 8.1 8.4 9.2 8.4



Periphyton

Diatoms 0.0 0.0 0.5 0.0




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Table6.14 WUA(m2/m)forarangeofspeciesattheminimumandmedianflows(cumecs)in the Kaniere River downstream of Kaniere Forks station under the existingsituation and the enhanced scheme. Predicted using the McKays Ford IFIMmodel.



0.26 0.38 2.9 0.68

Native fish


Common bully 8.9 9.6 6.9 10.4

Redfin bully 6.5 7.0 6.5 7.9

Koaro 0.9 1.1 3.5 1.6


Longfin eel (<300mm) 4.0 4.6 7.3 6.0

Longfin eel (>300mm) 4.2 4.7 4.3 5.7

Shortfin eel (<300mm) 8.2 8.7 7.9 9.4

Shortfin eel (>300mm) 4.8 5.3 3.8 6.1


Trout

Brown trout, <100mm 2.8 3.2 6.1 4.3



Macroinvertebrates



Elmidae 8.4 8.8 8.0 9.4



Periphyton

Diatoms 0.0 0.0 3.2 0.1




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Table6.15 WUA(m2/m)forarangeofspeciesattheminimumandmedianflows(cumecs)in the Kaniere River downstream of McKays Creek station under the existingsituation and the enhanced scheme. Predicted using the McKays Ford IFIMmodel.



0.82 0.74 7.5 9.0

Native fish


Common bully 10.5 10.4 4.5 4.3

Redfin bully 8.0 7.9 4.2 4.0

Koaro 1.8 1.6 2.9 2.7


Longfin eel (<300mm) 6.4 6.0 4.4 4.0

Longfin eel (>300mm) 5.9 5.7 2.8 2.5

Shortfin eel (<300mm) 9.8 9.4 4.1 3.7

Shortfin eel (>300mm) 6.2 6.1 2.3 2.2


Trout

Brown trout, <100mm 4.6 4.3 4.3 3.7



Macroinvertebrates



Elmidae 9.4 9.4 6.5 6.2



Periphyton

Diatoms 0.1 0.1 6.8 6.2




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6.4.3FluctuatingwaterlevelsinLakeKaniere

TherewillbenochangetotheconsentedoperatingrangeofLakeKaniere,whichis‐

0.2mto1m,undertheenhancedscheme,withnolakereleasesforpowergeneration

occurringat lake levelsbelow ‐0.1manda reduced flowrangebetween ‐0.1mand

0.2m (Palmer2010).However, theamountof time that the lake isat levelswithin

thisrangewillchange(Table6.16).Undertheenhancedschememedianandmean

lake levelswill decrease by 0.54m and 0.43m respectively relative to the existing

situation,with thepercentof timethat thelakeis spillingdecreasing to8%(Table

6.16).Suchchangesmaypotentiallyadverselyimpactaquaticplantcommunitiesin

thelittoralzoneofthelake;however,anyeffectsareanticipatedtobeminorasmost

species are present at a range of depths, the changes are within the existing

operatingrange,andvariations in lake levelwill take place over periodsofweeks

ratherthandailyfluctuations(Table2.2).Areductioninthepercentoftimethatthe

lakeis spillingmayaffect fishpassage(refer toearlierdiscussioninSection6.2.4),

butthiscouldbemitigatedthroughtheprovisionofreleaseflows,withinthelimits

of control gate operation, timed to coincide with peak migration periods for key

species(e.g.,eels).

Table6.16 Lake Kaniere water levels under the existing situation and enhanced scheme(datafromTable6.2.1Palmer2010).

Lake Existing Enhanced

Median lake level (m) 0.94 0.40

Mean lake level (m) 0.89 0.46

Percent of time spilling (above 1.0m) 42 8

Percent of time level below 0.2m 2 28

Daily fluctuations in the level of Lake Kaniere as a result of schemeoperation are

minor,withdailyfluctuationsgreaterthan2cmoccurringlessthan50%ofthetime

(Figure 6.23). The maximum daily change in lake level that can be achieved as a

resultofschemeoperationwouldbelessthan5cm,underconditionswherethereis

noinflow to thelakeand themaximumoutflowof8cumecsismaintained (Figure

6.24,Palmer2010).Suchminorvariationwouldhavea lessthanminimaleffecton

thelake’s littoralcommunities includingplantcommunities.Thelargestchangesin

lakelevelobserved(10cmandgreater)areduetonaturalincreasesassociatedwith

rainfallevents(Figure6.24,Palmer2010).


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Lake Kaniere daily level change distribution (2002-2008)

0

0.02

0.04

0.06

0.08

0.1

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Percent time value is exceeded

Daily c

han

ge m

(D

aily 3

hr

max -

daily 3

hr

min

)

Lake Kaniere level (Actual)

Lake Kaniere level (W8M8K0)

Table6.23 Lake Kaniere daily water level change (m) under the existing (Actual) and


6.4.4FluctuatingflowsintheKaniereRiver

Hydroelectricpowerschemesthatoperateinadailypeakingfashiontypicallycause

flow fluctuations in rivers downstreamof the powerstationdischargepoint.Daily

flow fluctuations are not natural and typically provide a ‘foreign’ physical

environment thatriverorganismsarenotnecessarilyadaptedto.Rapidchangesin

flow fluctuations can cause significant changes in the physical environment. The

low‐flowendofthecyclemaydewaterthechanneledge,affectingthesuitabilityof

thisenvironmentforspeciesadaptedtolivinginslowwater,shallowenvironments,

orspecieswhosimplyareincapableofmovingwiththespeedoftherecedingwater

level(i.e.,stranding).Thehigh‐flowendofthecyclemayresultinmid‐channelwater

depths and velocities exceeding the tolerance of species typically found in this

environment.

The existing operation of the Kaniere Forks and McKays Creek schemes does not

includepeakingand thereforedoesnottypicallyresult indailyflowfluctuationsin

Documents

et al. - Westland District Council · PDF filetaxonomic resolution that were used for identification, two invertebrate species were ... but is likely to be an error (Palmer 2010)